TM 9-2320-272-24-4
5-18. FUEL PUMP SETUP AND CALIBRATION (Contd)
j. Testing and Adjusting Fuel Pressure
NOTE
Throttle shaft internal adjusting screw is covered by a throttle
shaft ball in the end of throttle shaft.
CAUTION
Be careful not to damage bore of throttle shaft when drilling out
ball.
1.
Center punch and drill ball (6) out of fuel pump throttle shaft (7) with 1/4 in. drill bit.
2.
Screw internal fuel adjusting screw located in fuel pump throttle shaft (7) inward to increase fuel
pressure and outward to decrease fuel pressure until it is set to 172-178 psi (1186-1227 kPa).
3.
After fuel pressure is adjusted, insert new throttle shaft ball (6) with throttle shaft installation tool.
k . Testing and Adjusting Governor Fuel Pressure
1.
Adjust fuel pump (3) speed to 1,500 rpm.
2.
Place selector valve (4) on test stand (2) in ROTAMETER position.
3.
Place fuel throttle lever (5) to wide-open position.
4.
Set fuel flow to 2.30 pph with the fuel control valve (1).
5.
If fuel pressure is not 100-106 psi (689-730 kPa), check governor cutoff rpm (task e).
l. Checking and Adjusting Governor Weight Pressure
1.
Adjust fuel pump (3) speed to 1,000 rpm.
2.
Place throttle lever (5) to wide-open position.
3.
Place selector valve (4) in ROTAMETER position.
4.
Set fuel flow to 150 pph with fuel flow control valve (1).
NOTE
Shims are available in 0.005 and 0.010 in. (0.13 and 0.25 mm)
thickness. Do not change setting more than 0.020 in. (0.508 mm)
from specification.
5.
If fuel pressure is greater than 58 psi (399 kPa), decrease pressure by removing shims from behind
weight plunger.
6.
If fuel pressure is less than 50 psi (335 kPa), increase pressure by adding shims (para. 5-17).
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